Why I Don’t Deny – Part 1

I have often been asked “Why do you deny climate change?” I am always stumped by the question. It is rather like being asked “Why do you torture innocent animals?” The questioner is not merely asking for information, they are always making an accusation — an accusation that they consider very serious and a threat to themselves and others.

The reason it stumps me is that, as you have guessed already, I do not deny climate change (and I do not torture innocent animals — nor even guilty ones). And there is nothing about me or my behavior, present or past, that I am aware of, that would lead any reasonable person to think such a thing of me.

I am thoroughly guilty though of being very skeptical of what is generally referred to as the Climate Consensus — usually said to be represented by the latest reports and policy recommendations put out by the Intergovernmental Panel on Climate Change (IPCC) and its supporters; political, ideological and scientific. I suppose it is this that leads to the false accusation of “denying climate change”.

And there is the crux of the matter — it is something in the mind of the accuser, not any action of the accused, which leads to the false accusation.

MY DENIAL:

I deny that I am a Climate Denier, a Global Warming denier or any other kind of a “denialist”.

WHY I DON’T DENY:

I do not deny either of the two primary claims of the Global Warming Movement:

1. Global Warming is happening2. Human activity causes [some of] it.

Here’s why I don’t deny #1: Global Warming is happening.

I am perfectly happy to accept that the “world” (the “global climate”) has warmed since the late 1800s. We know that the date of 1880/1890 is picked for the starting point of most of the contemporary consensus view plots — purportedly because it represents “the start of the modern industrial era”, this despite the fact that even the IPCC does not claim that “CO2 induced global warming” started at that date. Let’s take a closer look at Lamb and Lamb_modified_by_Jones:

We all know that Lamb was showing a stylized “schematic” view of Central England temperatures — and Jones 2007 re-does the analysis with very slightly different results, then overlays (in blue) the measured Central England through 2007. This graph contains the seed of my certainty that “global warming is happening” — which, in un-politicized language would be something like: “The Earth’s general climate has warmed since a bit before 1700 CE — i.e., for the last 300+ years.” Here’s Spencer 2007:

And if you prefer, here’s the NOAA version with comparisons of various reconstructions :

They all show cooling to approximately 1650 – 1700 and general warming since then.

From where does my skepticism arise then? Well, there is no more — general warming started about 1650-1700, maybe a little earlier, and has been ongoing. When warming doesn’t start is 1880/1890 — it starts a hundred and fifty to two hundred years earlier — earlier than the start of the increased CO2 output of the modern Industrial Era. This makes me very skeptical indeed of the claim that the industrial revolution and modern warming are intrinsically entwined.

And I think that it is a good thing that it has warmed since 1700. The Little Ice Age years, up thru the 16 and 17 hundreds, were hard times for farmers (and thus whole populations) in North America and Europe, as attested to by contemporary accounts of crop failures and hard winters.

To my knowledge, this point is not controversial or even contested. In the Consensus Worldview, it is simply over-looked and not mentioned. Truthfully, since the facts don’t match the narrative — the narrative that global warming was caused by the start of the Industrial Revolution and its subsequent CO2 emissions — this fact seems to have been down played or ignored.

What does the IPCC say?“Warming of the climate system is unequivocal.” — IPCC AR5 SPM 1.1

Well, I couldn’t agree more — moreover, it has been warming since about 1650-1700, two hundred years before the Industrial Revolution starts pouring out CO2.

Without arguing about when “history” began, we can stipulate that the graph the European Geophysical Union gives us is an “accurate enough” picture of CO2 concentrations over the last thousand years. CO2 remains a shaky 275-290 ppm for 800 years and then begins to show a rise around 1850, finally breaking into new territory circa 1880-1890 — the start of the modern Industrial Era. The Wiki offers us the following, again confirming that CO2 does not begin to rise until 1890-1900, long after temperatures begin to rise.

Atmospheric CO2 has been rising — but is there doubt about this? — “ … recent anthropogenic emissions of green-house gases are the highest in history.” ?

While it is not easy to measure atmospheric CO2 concentrations, it has been being done for quite some time….and we have been able to guess about human greenhouse-gas emissions and their sources. [These are naturally abject guesses, but we needn’t argue with them on that account — they are our “best guesses”).

We see that recent emissions are highest, at least in this history, but notice that cumulatively up to 1970 (see the right hand inset bar graph), Forestry and other land use accounts for more than 50% of all CO2 emissions. This surprised even me — I was expecting a pretty big contribution from the clear-cutting and conversion into pasture and farmland of much of Europe and North America east of the Mississippi River — but I had no idea that Forestry and Land Use accounts for >50% all the way to 1970 –and that’s nineteen seventy, not eighteen seventy. By some proxies, global surface temperature had been rising for 300 years by 1970.

Keeping that fact in mind, let’s see what else the IPCC has to say about causes:

“Anthropogenic greenhouse gas emissions have increased since the pre-industrial era, driven largely by economic and population growth, and are now higher than ever. This has led to atmospheric concentrations of carbon dioxide, methane and nitrous oxide that are unprecedented in at least the last 800,000 years. Their effects, together with those of other anthropogenic drivers, have been detected throughout the climate system and are extremely likely to have been the dominant cause of the observed warming since the mid-20th century.”

The IPCC in their synthesis report for policy makers says that human emissions of greenhouse gases and “other anthropogenic drivers,” are “extremely likely to have been the dominant cause of the observed warming since the mid-20th century.”

I would have used slightly different points and alternate wordings — but the essence would be the same.

The IPCC Consensus general position is shown on the left — CO2 (and other greenhouse gases) are the primary “forcing” of climate — with changes in CO2 causing changing climate (basically warming) — this warming amplified by feedbacks, like increased water vapor and clouds.

On the right is Dr. Curry’s general view — I share much the same viewpoint. I would have placed place more emphasis this:

So far, I agree with all the facts, but don’t agree that recent CO2 (and other) emissions are “the dominant cause of the observed warming since the mid-20th century.” I agree neither with the attribution of CO2 as dominate or the effect size.

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If you aren’t yet bored to tears, you can find out more on my reasons for that in Part 2, to be published in the next day or so.